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Animal and Plant Health Inspection Service
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Asian Gypsy Moth

The Asian gypsy moth is a serious threat to our country’s landscapes and natural resources.

Asian gypsy moths (AGM, including Lymantria dispar asiatica, Lymantria dispar japonica, Lymantria albescens, Lymantria umbrosa, and Lymantria post¬alba) are exotic pests not known to occur in the United States. If they would become established here, they could cause serious, widespread damage to our country’s landscape and natural resources. AGMs are similar to the European gypsy moth found in the northeastern United States, but have a much broader host range. Each female moth can lay hundreds of eggs that, in turn, yield hundreds of voracious caterpillars that may feed on more than 500 tree and shrub species. Large AGM infestations can completely defoliate trees. This defoliation can severely weaken trees and shrubs, making them more susceptible to disease. Repeated defoliation can lead to the death of large sections of forests, orchards and landscaping. AGM females are also active fliers. Their ability to fly long distances makes it probable that AGMs could quickly spread throughout the United States.

  • Recently detected in Washington State, Oregon, Georgia, Oklahoma and South Carolina.

  • Ongoing surveys in those states will help determine whether infestations are present and what follow-up actions may be needed to address them.

A wide variety of North American tree and shrub species, including:

  • Alder

  • Larch

  • Sweetgum

  • Apple

  • Popular

  • Oak

  • Willow

  • Linden

  • Elm

  • Ships, cargo containers and some types of cargo coming to the United States from Asian countries where AGMs are known to exist.

  • Egg masses on tree trunks, limbs and leaves, as well as on stones, walls, logs, lawn furniture and other outdoor objects. Egg masses are covered with buff or yellowish fuzz and average 1 ½ inches by ¾ inches wide, but can be as small as a dime
  • Caterpillars feeding on tree and shrub leaves. Newly hatched caterpillars are approximately 1/8 inch in length and tan in color. Mature caterpillars may range from 2 to 3 ½ inches in length and have two rows of blue and red spots on their backs. The mature caterpillar is most often a mottled dark gray color, but can vary from yellow to black.

  • Adult moths are attracted to outdoor lighting and most active at dusk. Adult male moths have grayish-brown wings and a wingspan of 1 ½ inches. Adult female moths are white and larger, with wingspans of up to 3 ½ inches.

  • Defoliated trees

  • Report any findings of egg masses, caterpillars, adult moths, or defoliated trees to Federal or State agriculture officials.

  • Cooperate with any restrictions in your local area that might be imposed because of an AGM detection.

  • Allow authorized agricultural workers access to property to place and inspect insect-monitoring traps.


What's at Risk from the Asian Gypsy Moth:

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